In general, in order to reduce wasteful power consumption, some image forming devices such as copiers, printers, facsimile devices or multi-function machines, are constituted so to be able to switch to a power saving mode if a period in which no processing is performed continues for a predetermined amount of time in a normal mode, in which image forming processes are possible. For instance, when a copier is switched to the power saving mode, processes such as reducing the temperature of the fixing roller are performed.
Conventionally, this type of image forming device is provided with an operation panel for performing various setting operations. Thus, switches for various setting operations, a liquid crystal display unit for verifying setting operations and the like, are located on this operation panel.
In this case, in the prior art, a control process is carried out, in which a backlight light source, consisting of an LED or the like in the liquid crystal display unit that is provided on the control panel, is illuminated in the normal mode, but in the power saving mode, the backlight light source is turned off.
However, when in such a power saving mode, if a control process that turns off a backlight light source in the liquid crystal display unit is performed, it is difficult to distinguish this situation from a situation in which the power switch for the main power source is off. Thus, confusion arises, and the user may be misled into thinking that the power switch is off, and may turn the power switch on and off again, when in reality the device was merely switched to power saving mode.
The present invention was devised in view of the above problem, and an object thereof is to provide an image forming device with better usability than was conventional, by allowing an observer to clearly recognize which state the device is currently in: normal mode, power saving mode or power source off mode.